Understanding Linux filesystems: ext4 and Beyond

The majority of modern Linux distributions default to the ext4 filesystem, just as previous Linux distributions defaulted to ext3, ext2, and—if you go back far enough—ext.

If you're new to Linux—or to filesystems—you might wonder what ext4 brings to the table that ext3 didn't. You might also wonder whether ext4 is still in active development at all, given the flurries of news coverage of alternate filesystems such as btrfs, xfs, and zfs.

We can't cover everything about filesystems in a single article, but we'll try to bring you up to speed on the history of Linux's default filesystem, where it stands, and what to look forward to.

I drew heavily on Wikipedia's various ext filesystem articles, kernel.org's wiki entries on ext4, and my own experiences while preparing this overview.